JTS基本概念和使用

x33g5p2x  于2022-05-20 转载在 其他  
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简介

  1. JTS是加拿大的 Vivid Solutions公司做的一套开放源码的 Java API。它提供了一套空间数据操作的核心算法。为在兼容OGC标准的空间对象模型中进行基础的几何操作提供2D空间谓词API。

操作

  1. 表示Geometry对象

  2. Geometry类型介绍见另一篇文章:WKT WKB和GeoJSON

package com.alibaba.autonavi;

import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryCollection;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.LineString;
import com.vividsolutions.jts.geom.LinearRing;
import com.vividsolutions.jts.geom.Point;
import com.vividsolutions.jts.geom.Polygon;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.MultiLineString;
import com.vividsolutions.jts.geom.MultiPoint;
import com.vividsolutions.jts.io.ParseException;
import com.vividsolutions.jts.io.WKTReader;

public class GeometryDemo {

    private GeometryFactory geometryFactory = new GeometryFactory();

    /**
     * create a point
     * @return
     */
    public Point createPoint(){
        Coordinate coord = new Coordinate(109.013388, 32.715519);
        Point point = geometryFactory.createPoint( coord );
        return point;
    }
    
    /**
     * create a point by WKT
     * @return
     * @throws ParseException 
     */
    public Point createPointByWKT() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        Point point = (Point) reader.read("POINT (109.013388 32.715519)");
        return point;
    }
    
    /**
     * create multiPoint by wkt
     * @return
     */
    public MultiPoint createMulPointByWKT()throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        MultiPoint mpoint = (MultiPoint) reader.read("MULTIPOINT(109.013388 32.715519,119.32488 31.435678)");
        return mpoint;
    }
    /**
     * 
     * create a line
     * @return
     */
    public LineString createLine(){
        Coordinate[] coords  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};
        LineString line = geometryFactory.createLineString(coords);
        return line;
    }
    
    /**
     * create a line by WKT
     * @return
     * @throws ParseException
     */
    public LineString createLineByWKT() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        LineString line = (LineString) reader.read("LINESTRING(0 0, 2 0)");
        return line;
    }
    
    /**
     * create multiLine 
     * @return
     */
    public MultiLineString createMLine(){
        Coordinate[] coords1  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};
        LineString line1 = geometryFactory.createLineString(coords1);
        Coordinate[] coords2  = new Coordinate[] {new Coordinate(2, 2), new Coordinate(2, 2)};
        LineString line2 = geometryFactory.createLineString(coords2);
        LineString[] lineStrings = new LineString[2];
        lineStrings[0]= line1;
        lineStrings[1] = line2;
        MultiLineString ms = geometryFactory.createMultiLineString(lineStrings);
        return ms;
    }
    
    /**
     * create multiLine by WKT
     * @return
     * @throws ParseException
     */
    public MultiLineString createMLineByWKT()throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        MultiLineString line = (MultiLineString) reader.read("MULTILINESTRING((0 0, 2 0),(1 1,2 2))");
        return line;
    }
    
    /**
     * create a polygon(多边形) by WKT
     * @return
     * @throws ParseException
     */
    public Polygon createPolygonByWKT() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        Polygon polygon = (Polygon) reader.read("POLYGON((20 10, 30 0, 40 10, 30 20, 20 10))");
        return polygon;
    }
    
    /**
     * create multi polygon by wkt
     * @return
     * @throws ParseException
     */
    public MultiPolygon createMulPolygonByWKT() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        MultiPolygon mpolygon = (MultiPolygon) reader.read("MULTIPOLYGON(((40 10, 30 0, 40 10, 30 20, 40 10),(30 10, 30 0, 40 10, 30 20, 30 10)))");
        return mpolygon;
    }
    
    /**
     * create GeometryCollection  contain point or multiPoint or line or multiLine or polygon or multiPolygon
     * @return
     * @throws ParseException
     */
    public GeometryCollection createGeoCollect() throws ParseException{
        LineString line = createLine();
        Polygon poly =  createPolygonByWKT();
        Geometry g1 = geometryFactory.createGeometry(line);
        Geometry g2 = geometryFactory.createGeometry(poly);
        Geometry[] garray = new Geometry[]{g1,g2};
        GeometryCollection gc = geometryFactory.createGeometryCollection(garray);
        return gc;
    }
    
    /**
     * create a Circle  创建一个圆,圆心(x,y) 半径RADIUS
     * @param x
     * @param y
     * @param RADIUS
     * @return
     */
    public Polygon createCircle(double x, double y, final double RADIUS){
        final int SIDES = 32;//圆上面的点个数
        Coordinate coords[] = new Coordinate[SIDES+1];
        for( int i = 0; i < SIDES; i++){
            double angle = ((double) i / (double) SIDES) * Math.PI * 2.0;
            double dx = Math.cos( angle ) * RADIUS;
            double dy = Math.sin( angle ) * RADIUS;
            coords[i] = new Coordinate( (double) x + dx, (double) y + dy );
        }
        coords[SIDES] = coords[0];
        LinearRing ring = geometryFactory.createLinearRing( coords );
        Polygon polygon = geometryFactory.createPolygon( ring, null );
        return polygon;
    }

    /**
     * @param args
     * @throws ParseException 
     */
    public static void main(String[] args) throws ParseException {
        GeometryDemo gt = new GeometryDemo();
        Polygon p = gt.createCircle(0, 1, 2);
        //圆上所有的坐标(32个)
        Coordinate coords[] = p.getCoordinates();
        for(Coordinate coord:coords){
            System.out.println(coord.x+","+coord.y);
        }
    }
}
  1. Geometry之间的关系

  2. 支持的空间操作包括

相等(Equals):几何形状拓扑上相等。
脱节(Disjoint):几何形状没有共有的点。
相交(Intersects):几何形状至少有一个共有点(区别于脱节)
接触(Touches):几何形状有至少一个公共的边界点,但是没有内部点。
交叉(Crosses):几何形状共享一些但不是所有的内部点。
内含(Within):几何形状A的线都在几何形状B内部。
包含(Contains):几何形状B的线都在几何形状A内部(区别于内含)
重叠(Overlaps):几何形状共享一部分但不是所有的公共点,而且相交处有他们自己相同的区域。
package com.alibaba.autonavi;

import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.io.ParseException;
import com.vividsolutions.jts.io.WKTReader;

/**
 * gemotry之间的关系
 *
 */
public class GeometryRelated {

    private GeometryFactory geometryFactory = new GeometryFactory();
    
    /**
     *  两个几何对象是否是重叠的
     * @return
     * @throws ParseException
     */
    public boolean equalsGeo() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");
        LineString geometry2 = (LineString) reader.read("LINESTRING(5 0, 0 0)");
        return geometry1.equals(geometry2);//true
    }
    
    /**
     * 几何对象没有交点(相邻)
     * @return
     * @throws ParseException
     */
    public boolean disjointGeo() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");
        LineString geometry2 = (LineString) reader.read("LINESTRING(0 1, 0 2)");
        return geometry1.disjoint(geometry2);
    }
    
    /**
     * 至少一个公共点(相交)
     * @return
     * @throws ParseException
     */
    public boolean intersectsGeo() throws ParseException{
        WKTReader reader = new WKTReader( geometryFactory );
        LineString geometry1 = (LineString) reader.read("LINESTRING(0 0, 2 0, 5 0)");
        LineString geometry2 = (LineString) reader.read("LINESTRING(0 0, 0 2)");
        Geometry interPoint = geometry1.intersection(geometry2);//相交点
        System.out.println(interPoint.toText());//输出 POINT (0 0)
        return geometry1.intersects(geometry2);
    }

    /**
     * 判断以x,y为坐标的点point(x,y)是否在geometry表示的Polygon中
     * @param x
     * @param y
     * @param geometry wkt格式
     * @return
     */
    public boolean withinGeo(double x,double y,String geometry) throws ParseException {

        Coordinate coord = new Coordinate(x,y);
        Point point = geometryFactory.createPoint( coord );

        WKTReader reader = new WKTReader( geometryFactory );
        Polygon polygon = (Polygon) reader.read(geometry);
        return point.within(polygon);
    }
    /**
     * @param args
     * @throws ParseException 
     */
    public static void main(String[] args) throws ParseException {
        GeometryRelated gr = new GeometryRelated();
        System.out.println(gr.equalsGeo());
        System.out.println(gr.disjointGeo());
        System.out.println(gr.intersectsGeo());
        System.out.println(gr.withinGeo(5,5,"POLYGON((0 0, 10 0, 10 10, 0 10,0 0))"));
    }

}

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